Electric fuse



Oct. 26,1926. a 1,604,477

E. L. OGLE ELECTRIC FUSE Filed Oct. 27. 1921 2 Sheets-Sheet 2 agq Patented 0st. 26, 1926.

UNITED STATES PATENT OFFICE.

ELMER L. OGLE, OF CHICAGO, ILLINOIS, ASSIGNOE 'IO FEDERAL ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

ELECTRIC FUSE.

Application filed October 27, 1921. Serial No. 510,826

The invention relates to improvements in electric fuses and consists of the matters hereinafter described and more particularly pointed out in the appended claims.

The object of the invention is to simplify and improve the construction of electric fuses, more especially those designed for heavy loads, whereby they are made more ready of assembly and more'easily flexible in the matter of adjustment of the cartridge to the designed load.

The advantages of the improved fuse will appear as I proceed with my specification.

In the drawings Figure 1 is a view representing the improved fuse in side elevation;

Figure 2 is a view on a large scale, representing a longitudinal central section through the fuse; V

Figures 3, dand 5 are sectional views in planes indicatedrespectively by the lines 3-3, 4-4, and 55 of Figure 2;

Figure 6 is an end view of the fuse, showin the end with the fixed head";

Figure 7 is a perspective view of the fusible bars of the cartridge and their means of support;

Figure 8 is a perspective view of the removable head of the fuse;

Figure 9 is a perspective viewof an end of the fuse showing a modified form of the removable head.

Referring now to that embodiment of the invention illustrated in the drawings :1() indicates the body of the fuse, which is of the knife-blade contact type, and 11, 12 indicate the contact blades. 13 indicates the enclosed cartridge which contains the fusible member. The body is a heavy tube of insulating material, such as fibre or the like and is closed at its ends by metallic, tubular heads 14, 15 which carry the blades 11 and 12 respectively. 7

The one head 15 is permanently attached to the tube 10. The tubular part of the head closely embraces the end of the fibre tube 1'0, with itsflat head engaged against a fiat metal disc 16, which in' turn engages against" the. end of'the tube-10- and the head is fixed on the, tube; by means of rivets 17. The] blade 12 extends through a 51min the flat head and hasspa'ced ex"- anaem a, 12 which extend'through holes in the disc 16 andaref riveted against t "e inner-faee'efsaid disc;

The other head 14 is made in two separable parts, (see Figures 2, 3 and 8), namely a short tube 18, which is permanently at tached to the fibre tube by rivets 18 and inner and :outer flat discs 19, 20, which are attached together and secured to the as sociated blade 11 by means of spaced rivet extensions 11, 11 on said blade and which fit snugly within the open end of the metal tube 18 and against the end of the fibre tube 10, beyond which said metal tube extends a distance equal to the thickness of the two discs. The outer disc 20 has diametrically opposed cars 21, 21' which extend at right angles to the plane of the disc and embrace the tube 18 and are secured thereto by screws 21 ,the metal of the tube being upset through the fibre tube 10 and tapped to receive said screws. The projecting end of thetube 18 is notched to receive the radial disc extensions 21 of which the ears 21 are parts and the projecting part of the tube is bent adjacent said notches to provide pairs of spaced lugs 22 which engage at either side of the cars '21 andat once fix and determine the position of the disc 20 and the plane of the contact carried by it and securely lock said disc against rotative move ment. In the case of very large fuses, four cars 21?, instead of two as just described, are provided on the removable head of the fuse, as shown in Figure'9. In such case the metal tube 18 is provided with four pairs of lugs 22*. F roni the foregoing it is apparent that the removable part of the fuse head 14 comprising the discs 19, 20 and the connected'blade 11 is readily removable for the purpose of removing and replacing a fused cartridge and that it. is easily and quickly applied with its blade 11 always in the required plane, and that the blade is securely held, in" that plane by the lugs 22.

The cartridge 13 has a tubular body of insulating material which is closed at its ends by metal tubular'caps 24, 25. Each cap, is held on' the end of'the fibre" tube means of its tubular flangev gripped against theloutside" of the tube and a phi-- 'rality.of 'detentsflfi (see, nigme 5.) punched from the-head of the cap and engaged within the? end of" the tube;

'27 indicates thefusible element unit. This consists of; twb 1 metal, plugs 28, 29., l which constitute? t rminals? one; connected? to -reach rnetal cap ofth'e"cartridgeaiidb-fa plurality of fusible bars connecting and being supported by said plugs. The plugs 28, 29 are made cylindrical as shown and are provided in their proximate ends with diametric slots 30 to receive the ends of the fusible bars. 31 indicates the fusible bars themselves. As many of said bars 31 are used as are required to carry the load, each bar having a hole 32 to determine its effective cross section 1n a familiar manner. The bars 31 are arranged in parallel planes with their ends 31 in juxtaposition and engaged in the slots 30 of the plugs 28 and 29 and with their intermediate lengths 31 spaced apart as clearly illustrated in Figures 2 and 7. The ends 31 are riveted in their respective slots 30 by means of rivets 32 extending diametrically through suitable openings in the plugs and further secured and fixed therein by means of solder.

Each plug 28, 29 has a reduced end part 28 29 which extends through a suitable aperture in the associated cap with the radial shoulder 28 29 formed by the reduction abutting against the inner face of said cap. Each plug is also provided with a threaded aperture 33 to receive a screw 34 rotatively held in the proximate head of the fuse. The reduced end 28 of the plug 28 is upset against the outer face of the associated cap 24 of the cartridge (see Fig. 2). An apertured tell-tale-tag plate 35 (see Fig. 5) is engaged on the reduced end 29 of the plug 29 next to the outer face of the cap 25 and a washer 36, next to the plate 35, and all parts are secured to the plug and to each other by solder. The plate 35 is adapted to extend diametrically across the cap 25 beyond it so that an ape-rtured end 35 constituting the tell-tale-tag may be bent down against the metal tube 18 on the fuse in advance of the application of the removable head, in position to be engaged and held in place by one of the ears 21. To fix and determine the position of the plate 35, for purposes of assembly, spaced tongues 37 are punched from the cap 25 in position to engage the edges of said plate 35 when in the required position and adapted to be bent down to engage the outer face of said plate. Said tongues are not only of assistance for holding the plate 35 when assembling and soldering the parts but they also act to lock it in position against swinging movement on the end of the plug, after the parts have been attached together.

The manner of assembling the cartridge and of inserting or replacing an exploded cartridge will be apparent from the foregoing description. The fusible element 27 is made up in quantities with one, two, three or more fusible bars 31 for various loads. The simplicity of construction of the fusible element and its easy flexibility of adjustment to different loads are manifest. The fusible bars being rigidly connected to the plugs, 28, 29, the fusible element is readily handled as the plate 35 with its tell-tale-tag 35 is engaged on said reduced end, being first located in position between the lugs or detents 37 in the cap, whereupon said lugs are bent down to hold said plate in place. The washer 36 is next placed upon said reduced end 29 and solder applied to secure the parts together. The cartridge is now ready and its capacity is shown on the tell-tale tag 35*.

To load the fuse with a cartridge,--the cartridge is inserted in the fuse body and is then rotated until the threaded recess in the plug 28 may be engaged by the screw 34: in the fuse head 15. The screws as has been pointed out, are capable of a rotative movement, but are held in the heads against longitudinal move1nent,the screw-heads having flanges which are loosely gripped in a familiar way between the discs comprising the flat heads of the fuse. By means of the aforesaid screw the cartridge is drawn up towards the fuse head 15 until the exposed end of the plug 28 is engaged against the inner face of the fuse head. The fuse head 14; is then applied as already described.

The fuse heads and the cartridge caps are provided with vent openings 40, 41 respectively to relieve the pressure generated by the blowing of a cartridge.

By reason of the construction of fuse units as described, it is possible to manufacture a fuse unit of uniform resistance which will operate on electric circuits successfully in parallel, due to the fact that each fuse in the circuit will take its respective load, so that the load'is equally divided between the fuses.

I claim as my invention 1. In an electric fuse, a fusible unit comprising a pair of aligned terminals having threaded apertures in their remote ends, said ends being reduced in diameter, a fusible bar bridging the gap between said terminals and being connected to the proximate ends of said terminals, and a cartridge cap having an aperture through which the reduced end of one terminal extends, a telltale tag plate next to said cap provided with anaperture through which said reduced end extends, and a washer on the extreme end ofjsaid terminal next to said plate, the several parts being soldered together.

' 2. In an electric fuse, a'cartridge having a metallic cap with an aperture at a point located eccentrically therein, a fusible unit including a terminal With a reduced end extending through said cap, a tell-tale tag plate adapted to extend diametrically across said cap and to extend beyond said cap, said plate having an aperture to be engaged on the reduced end of said terminal, and means on said cap for defining the position of said plate.

3. In an electric fuse, a cartridge having a metallic cap with an aperture at a point located eccentrically therein, a fusible unit including a terminal with a reduced end extending through said cap, a tell-tale tag plate adapted to extend diametrically across said cap and to extend beyond said cap, said plate having an aperture to be engaged on the reduced end of said terminal, and lugs stamped out of said cap adapted to determine the position of said plate and to be bent into engagement With its outer face.

4. In an electric fuse, in combination with a tubular body of insulating material and a metal tube fixed on said body and projecting beyond it, a removable head comprising a flat circular head adapted to fit Within said metal tube aaginst the end of said tubular body, said circular head being provided With radial extensions having ears extending at right angles to said head and adapted to embrace said metal tube, the projectin end of said tube being provided with HOtCfilGS to receive said radial extensions, and With lugs to engage the 

